Industrial robot installation

Abstract

A robot installation in a production line includes at least one robot (1) of pendulum type, the arm system (10, 14) of which is pivotable about at least one axis (12). The secondary arm (14) of the robot and a counterweight (16) are so displaceably arranged on the primary arm (10) of the robot that the centre of gravity of the arm system lies on or in immediate proximity to the pivot axis (12) independently of the position of the secondary arm (14) on the primary arm (10). To this end, the counterweight (16) and the secondary arm (14) are movably interconnected by means of a rope (18) running around rope wheels (20) at the ends of the primary arm (10). When mounting several robots of this kind on a stand (34, 35) positioned across the production line (31), the robots are mounted symmetrically in pairs on opposed side walls of the overhead stand part (35).

What is claimed is: 
     
       1. An industrial robot installation including at least one robot of pendulum type, said robot comprising a robot stand rotatable about a first axis,   an arm system including a primary arm and a secondary arm, said primary arm being pivotably journalled in said stand about a second axis oriented transversely across the longitudinal direction of the primary arm, and said secondary arm being movably journalled on said primary arm,   a counterweight displaceably mounted on said primary arm for counterbalancing said arm system, and   a movement-transmitting mechanism interconnecting said secondary arm and said counterweight,   said secondary arm and said counterweight being simultaneously linearly displaceable towards and away from each other, respectively, on respective sides of said second axis such that, independently of the position of said secondary arm on said primary arm, the centre of gravity of said arm system is located on or in immediate proximity to said second axis.   
     
     
       2. A robot installation according to claim 1, in which the movement-transmitting mechanism comprises a rope or chain member (18) which interconnects the secondary arm (14) and the counterweight (16). 
     
     
       3. A robot installation according to claim 2, in which the rope or chain member (18) runs over deflector wheels (20) at the ends of the primary arm (10). 
     
     
       4. A robot installation according to one of claims 1-3, in which the counterweight is so arranged that the arm system is counterbalanced with respect to both of said axes (12, 13). 
     
     
       5. A robot installation according to one of claims 1-3, in which the counterweight and the secondary arm (14) are located on opposite sides of a plane extending through said second axis (12) and being parallel to the longitudinal axis of the primary arm. 
     
     
       6. A robot installation according to claim 1, in which an overhead stand (34), arranged across a production line (31), is supporting several robots (1), whose individual centres of gravity are substantially stationary independently of the operating position of the respective robot, said robots being arranged on opposite side walls of that part (35) of the stand (34) which is positioned over the production line (31) in such a way that the common centre of gravity of the robots lies in the central portion of said overhead stand part (35). 
     
     
       7. A robot installation according to claim 6, in which the robots (1) are arranged symmetrically in pairs on the overhead stand part (35). 
     
     
       8. A robot installation according to claim 6, in which the robots (1) are fixedly mounted on the opposite side walls of the overhead part (35) of an essentially U-shaped portal (34) straddling the production line (31). 
     
     
       9. A robot installation according to claim 6, in which the robots (1) are mounted in pairs opposite to each other on the overhead stand part (35).